Hypertension is a health problem affecting millions of people, requiring considerable expenditure of medical resources as well as imposing significant burdens on those who suffer from this condition. Hypertension generally involves resistance to the free flow of blood within a patient's vasculature, often caused by reduced volume stemming from plaque, lesions, and the like. Because blood vessels do not permit easy flow, the patient's heart must pump at higher pressure. In addition, reduced cross-sectional area results in higher flow velocity. In consequence, a patient's blood pressure may enter into the range of hypertension, i.e. greater than 140 mm Hg systolic/90 mm Hg diastolic. For a chronic disease, such as hypertension, where the negative outcomes such as stroke come as a result of a lifetime of exposure to elevated blood pressure. Oftentimes, such elevated blood pressure can persist for up to a year until the patient is seen in a clinic for an annual check-up, after which the patient's elevated blood pressure can be corrected using conventional means.
It has been recognized that the kidneys play a key role in blood pressure regulation, and a number of hypertension treatment approaches have focused on the kidneys, providing a number of pharmaceutical compounds aimed at promoting blood to flow through these organs. One treatment option has been to destroy some or all of the nerves innervating the kidneys through ablation, a process in which an therapeutic electrode, carried in an instrument such as an endoscope, is introduced into a patient's vasculature and navigated to a position within the renal artery. Electrical energy, operating at radio frequencies sufficient to ablate nerve tissue, is delivered to the electrode, resulting in destruction of the renal nerves.
This process, of course, is irreversible and carries the possibility of undesirable side effects. For example, it is known that renal nerve ablation can lead to neuroma formation and neuropathic pain at the site of the ablative lesion. Because the ablation of renal nerves causes permanent physiological alterations to the patient, it is often very difficult, if not impossible, to re-adjust the patient's blood pressure when needed (e.g., when the patient experience severe loss of blood).
Thus, a need remains to dynamically ameliorate hypertension without permanently affecting the renal nervous system.